What is the phenotype associated with zygotic gene mutations?

Video transcript

Hi, everyone. Let's look at our next problem in Drosophila, being homesickness for deleterious recessive mutations and psychotic genes leads to and we have answer choice is of a larvae with no contiguous body segments, be adults with displaced body parts. See embryonic lethality and d normal adults. Well, first, let's think of what the psychotic genes are. These are those genes expressed in the zygote immediately post fertilization. So, at the very beginning of embryonic development, and there's two types of those genes, the segmentation genes and the homoerotic jeans. And now let's think about the situation we're being asked to consider when an embryo is home, as I guess for deleterious recessive mutations. So, deleterious mutations of course are harmful And the embryo is expressing two copies of the mutated gene. Well, we can right away eliminate choice d normal adults um being homeless, I guess for deleterious mutation mutation. So early development is obviously not going to produce a normal adult. So we can eliminate choice D. So we've got these two A and B that involve significant problems going on with the embryo. Um and then choice C embryonic lethality. Well, when we got this individual homes, I guess for deleterious mutations that early in development, our answer choices, choice c embryonic lethality that embryo just cannot survive that significant problem early in development. Now, let's look at our other answer. Choices A and B to see why they're incorrect. Choice. A larvae with no contiguous body segments. Um This would occur when you have a mutation. Um It could be homesickness or hetero zegas, but in this case, it's not deleterious, doesn't lead to death of the embryo. Um But it has no body segments that would occur if there was a mutation in the segmentation genes. Since they're what directs that division of the embryo into large segments. But that's why I say isn't correct. Um As it would just result, not necessarily result of deleterious mutations of the embryos home as I guess for, but rather a non lethal mutation in the segmentation genes. Choice b adults with displaced body parts would result from mutations in homoerotic genes that we're not lethal. But since homoerotic genes direct the destination of cells as they develop into the anatomical structures, if something goes wrong with those jeans, you get, let you lead to things like um legs growing where antenna should be when you have a mutation, homoerotic genes. So not a lethal mutation but obviously causing some pretty significant issues in this case, but not our answer since that's not the result of Hamas's deleterious mutations. So again, in Drosophila being home is I guess for deleterious recessive mutations and psychotic genes leads to choice c embryonic lethality. See you in the next video.